CVE-2026-89596 - Vulnerability Details

- forcedeth: fix off-by-one when saving/restoring non-PCI config space

Description

In the Linux kernel, the following vulnerability has been resolved:

forcedeth: fix off-by-one when saving/restoring non-PCI config space

nv_suspend() and nv_resume() walk the non-PCI configuration space with

for (i = 0; i <= np->register_size/sizeof(u32); i++)

which runs one iteration too many. saved_config_space is declared as

u32 saved_config_space[NV_PCI_REGSZ_MAX/4];

and NV_PCI_REGSZ_VER3 is equal to NV_PCI_REGSZ_MAX (0x604), so on a VER3
device register_size/sizeof(u32) is exactly the array length and the last
iteration addresses one element past the end.

The element it lands on is np->name_rx[0..3]: saved_config_space[] is
followed immediately by char name_rx[IFNAMSIZ + 3], and char needs no
padding. Nothing observable is corrupted by that, because nv_request_irq()
rewrites name_rx with sprintf() before it is ever passed to request_irq().
The bug is the out-of-bounds access itself, which UBSAN reports and which
CONFIG_UBSAN_TRAP=y turns into a trap that aborts the running kernel code,
plus an MMIO read and, on resume, an MMIO writel() to base + 0x604, one
dword past the range the driver mapped:

np->base = ioremap(addr, np->register_size);

VER1 and VER2 devices stay inside the array, but they too get the stray
read and the stray write one dword past their own window.

Caught by UBSAN on an Apple Macmini3,1 (MCP79) during a deep S3 cycle.
The splat below is trimmed: the build path in the file name, the CPU
and taint lines, the Workqueue line, the "?" hint frames, and the
frames below device_suspend are all cut. The kernel was tainted, with
an out-of-tree nouveau and CPU_OUT_OF_SPEC; forcedeth itself was the
stock module.

UBSAN: array-index-out-of-bounds in drivers/net/ethernet/nvidia/forcedeth.c:6225:25
index 385 is out of range for type 'u32 [385]'
Call Trace:
dump_stack_lvl+0x5d/0x80
ubsan_epilogue+0x5/0x2b
__ubsan_handle_out_of_bounds.cold+0x54/0x59
__this_module+0xe398c/0xe9010 [forcedeth]
pci_pm_suspend+0x80/0x170
dpm_run_callback+0x51/0x160
device_suspend+0x1a2/0x4a0
...

Both loops are hit. UBSAN reports each source location only once per module
load (__ubsan_handle_out_of_bounds() calls suppress_report(), which does
test_and_set_bit(REPORTED_BIT, ...) on the struct source_location), so the
two splats land in the first S3 cycle after the module is loaded and later
cycles are silent even though the access still runs off the end every time.
In that first cycle line 6225 is reported from pci_pm_suspend and line 6240
from pci_pm_resume.

The same off-by-one was fixed in nv_get_regs() by commit ba9aa134287f
("forcedeth: fix buffer overflow") in 2012; these two loops were missed.
The suspend and resume side was reported on LKML in September 2013 by Marc
Weber, with the same analysis and the same one-character fix, but the patch
was attached rather than sent inline and the thread ended there.

Use < instead of <=, which saves and restores exactly register_size bytes.

Published: 2026-09-11

Score: 7.1 High

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

An off‑by‑one error in the forcedeth driver causes the nv_suspend() and nv_resume() routines to read from and write to one element past the end of a statically allocated array while copying non‑PCI configuration space. The out‑of‑bounds access triggers a UBSAN trap that aborts the kernel when UBSAN is enabled, or silently performs an illegal MMIO read or write when UBSAN is disabled, resulting in a kernel crash that brings the affected system down and yields a denial‑of‑service condition.

Affected Systems

All Linux kernels that include the forcedeth driver without the loop‑bound fix commit (changing '<=' to '<') and that support suspend or resume distribution forcedeth module are vulnerable.

Risk and Exploitability

The CVSS score of 7.1 indicates high severity, while the EPSS score is below 1 %, implying a very low probability of exploitation. The vulnerability is not listed in CISA KEV. It is inferred that an attacker would need local system access or the ability to trigger suspend/resume cycles for a device managed by forcedeth—e.g., by sending a power‑management event or manipulating the power state. Because the fault leads to a kernel abort when UBSAN is enabled, the impact is largely limited to system availability rather than confidentiality or integrity. The overall risk remains high due to the severity of the crash exploitation.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`1a1ca86158eee303af5270338695f90bc7ae02b3`	affected	< effd589568b2c4399894a23000286210c60af6d7
`1a1ca86158eee303af5270338695f90bc7ae02b3`	affected	< 702aa4a44c87026b97b1da5c5ca80e1fa8a9875a
`1a1ca86158eee303af5270338695f90bc7ae02b3`	affected	< fc71c6c3d3e3bb17474dcd1162aea6783a452a64
`1a1ca86158eee303af5270338695f90bc7ae02b3`	affected	< c4d5953582463f45e48b14ef9815e5fb636f7e1f
`1a1ca86158eee303af5270338695f90bc7ae02b3`	affected	< 9379f8527ca60d92715c90b32f1b477de9ec32cb
`1a1ca86158eee303af5270338695f90bc7ae02b3`	affected	< 0c3f4544ff3873594c8af1b907b4ac4e6d5ce005
`1a1ca86158eee303af5270338695f90bc7ae02b3`	affected	< c4f196bfeedd71e56aba4b63bd8f919edb2f7056
`1a1ca86158eee303af5270338695f90bc7ae02b3`	affected	< 9393f1d656a79693e0c123ff7bc7c5c0f708046d

Linux

affected

Version	Status	Constraints
`2.6.27`	affected	—
`0`	unaffected	< 2.6.27
`5.10.270`	unaffected	≤ 5.10.*
`5.15.221`	unaffected	≤ 5.15.*
`6.1.188`	unaffected	≤ 6.1.*
`6.6.157`	unaffected	≤ 6.6.*
`6.12.109`	unaffected	≤ 6.12.*
`6.18.50`	unaffected	≤ 6.18.*
`7.2.4`	unaffected	≤ 7.2.*
`7.3-rc1`	unaffected	≤ *

No data.

Vendor Product Confidence Versions

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`[1a1ca86158eee303af5270338695f90bc7ae02b3,9379f8527ca60d92715c90b32f1b477de9ec32cb)`	affected	code_commit	—
`[1a1ca86158eee303af5270338695f90bc7ae02b3,0c3f4544ff3873594c8af1b907b4ac4e6d5ce005)`	affected	code_commit	—
`[1a1ca86158eee303af5270338695f90bc7ae02b3,c4f196bfeedd71e56aba4b63bd8f919edb2f7056)`	affected	code_commit	—
`[1a1ca86158eee303af5270338695f90bc7ae02b3,9393f1d656a79693e0c123ff7bc7c5c0f708046d)`	affected	code_commit	—

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`2.6.27`	affected	semver	—
`[0,2.6.27)`	unaffected	generic	—
`[6.12.109,6.13.0)`	unaffected	semver	—
`[6.18.50,6.19.0)`	unaffected	semver	—
`[7.2.4,7.3.0)`	unaffected	semver	—
`[7.3-rc1,*]`	unaffected	generic	—

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Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Update the Linux kernel or driver package to a version that incorporates the forcedeth off‑by‑one fix (commit that changes the loop to use '<' instead of '<=' )
If an immediate kernel update is not feasible, disable or blacklist the forcedeth driver
Configure the kernel with UBSAN enabled and trap mode to immediately break on array‑index violations, thereby preventing silent corruption although it may result in a kernel panic

Generated by OpenCVE AI on September 15, 2026 at 21:29 UTC.

Tracking

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Advisories

Source	ID	Title
Debian DSA	DSA-6528-1	linux security update

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00185.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/0c3f4544ff3873594c8af1b907b4ac4e6d5ce005
https://git.kernel.org/stable/c/702aa4a44c87026b97b1da5c5ca80e1fa8a9875a
https://git.kernel.org/stable/c/9379f8527ca60d92715c90b32f1b477de9ec32cb
https://git.kernel.org/stable/c/9393f1d656a79693e0c123ff7bc7c5c0f708046d
https://git.kernel.org/stable/c/c4d5953582463f45e48b14ef9815e5fb636f7e1f
https://git.kernel.org/stable/c/c4f196bfeedd71e56aba4b63bd8f919edb2f7056
https://git.kernel.org/stable/c/effd589568b2c4399894a23000286210c60af6d7
https://git.kernel.org/stable/c/fc71c6c3d3e3bb17474dcd1162aea6783a452a64
https://nvd.nist.gov/vuln/detail/CVE-2026-89596
https://www.cve.org/CVERecord?id=CVE-2026-89596

History

Mon, 14 Sep 2026 12:30:00 +0000

Type	Values Removed	Values Added
References		https://git.kernel.org/stable/c/702aa4a44c87026b97b1da5c5ca80e1fa8a9875a https://git.kernel.org/stable/c/c4d5953582463f45e48b14ef9815e5fb636f7e1f https://git.kernel.org/stable/c/effd589568b2c4399894a23000286210c60af6d7 https://git.kernel.org/stable/c/fc71c6c3d3e3bb17474dcd1162aea6783a452a64

Sun, 13 Sep 2026 06:45:00 +0000

Type	Values Removed	Values Added
Metrics	cvssV3_1 `{'score': 4.7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'}`	cvssV3_1 `{'score': 7.1, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H'}`

Sat, 12 Sep 2026 00:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-125
References		https://nvd.nist.gov/vuln/detail/CVE-2026-89596 https://www.cve.org/CVERecord?id=CVE-2026-89596
Metrics	threat_severity `None`	cvssV3_1 `{'score': 4.7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'}` threat_severity `Important`

Fri, 11 Sep 2026 23:45:00 +0000

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: forcedeth: fix off-by-one when saving/restoring non-PCI config space nv_suspend() and nv_resume() walk the non-PCI configuration space with for (i = 0; i <= np->register_size/sizeof(u32); i++) which runs one iteration too many. saved_config_space is declared as u32 saved_config_space[NV_PCI_REGSZ_MAX/4]; and NV_PCI_REGSZ_VER3 is equal to NV_PCI_REGSZ_MAX (0x604), so on a VER3 device register_size/sizeof(u32) is exactly the array length and the last iteration addresses one element past the end. The element it lands on is np->name_rx[0..3]: saved_config_space[] is followed immediately by char name_rx[IFNAMSIZ + 3], and char needs no padding. Nothing observable is corrupted by that, because nv_request_irq() rewrites name_rx with sprintf() before it is ever passed to request_irq(). The bug is the out-of-bounds access itself, which UBSAN reports and which CONFIG_UBSAN_TRAP=y turns into a trap that aborts the running kernel code, plus an MMIO read and, on resume, an MMIO writel() to base + 0x604, one dword past the range the driver mapped: np->base = ioremap(addr, np->register_size); VER1 and VER2 devices stay inside the array, but they too get the stray read and the stray write one dword past their own window. Caught by UBSAN on an Apple Macmini3,1 (MCP79) during a deep S3 cycle. The splat below is trimmed: the build path in the file name, the CPU and taint lines, the Workqueue line, the "?" hint frames, and the frames below device_suspend are all cut. The kernel was tainted, with an out-of-tree nouveau and CPU_OUT_OF_SPEC; forcedeth itself was the stock module. UBSAN: array-index-out-of-bounds in drivers/net/ethernet/nvidia/forcedeth.c:6225:25 index 385 is out of range for type 'u32 [385]' Call Trace: dump_stack_lvl+0x5d/0x80 ubsan_epilogue+0x5/0x2b __ubsan_handle_out_of_bounds.cold+0x54/0x59 __this_module+0xe398c/0xe9010 [forcedeth] pci_pm_suspend+0x80/0x170 dpm_run_callback+0x51/0x160 device_suspend+0x1a2/0x4a0 ... Both loops are hit. UBSAN reports each source location only once per module load (__ubsan_handle_out_of_bounds() calls suppress_report(), which does test_and_set_bit(REPORTED_BIT, ...) on the struct source_location), so the two splats land in the first S3 cycle after the module is loaded and later cycles are silent even though the access still runs off the end every time. In that first cycle line 6225 is reported from pci_pm_suspend and line 6240 from pci_pm_resume. The same off-by-one was fixed in nv_get_regs() by commit ba9aa134287f ("forcedeth: fix buffer overflow") in 2012; these two loops were missed. The suspend and resume side was reported on LKML in September 2013 by Marc Weber, with the same analysis and the same one-character fix, but the patch was attached rather than sent inline and the thread ended there. Use < instead of <=, which saves and restores exactly register_size bytes.
Title		forcedeth: fix off-by-one when saving/restoring non-PCI config space
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/0c3f4544ff3873594c8af1b907b4ac4e6d5ce005 https://git.kernel.org/stable/c/9379f8527ca60d92715c90b32f1b477de9ec32cb https://git.kernel.org/stable/c/9393f1d656a79693e0c123ff7bc7c5c0f708046d https://git.kernel.org/stable/c/c4f196bfeedd71e56aba4b63bd8f919edb2f7056

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-09-11T19:44:58.797Z

Updated: 2026-09-14T12:01:19.256Z

Reserved: 2026-09-11T19:38:34.731Z

Link: CVE-2026-89596

Vulnrichment

No data.

NVD

Status : Received

Published: 2026-09-11T20:19:44.310

Modified: 2026-09-14T13:19:13.637

Link: CVE-2026-89596

Redhat

Severity : Important

Publid Date: 2026-09-11T19:44:58Z

Links: CVE-2026-89596 - Bugzilla

OpenCVE Enrichment

Updated: 2026-09-15T21:30:16Z

Weaknesses

CWE-125
Out-of-bounds Read

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact High

Availability Impact High

User Interaction None

Subscriptions

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